Help with a jerry rig cooling system
On Jul 26, 6:13*am, wrote:
Beatrice writes:
... In reference to a new house here in Eugene Or...
NREL says August is the warmest month in Eugene, with a 67.6 F daily
average and a 53.2 and 81.8 min and max and a 53.3 deep ground temp
and humidity ratio w = 0.0085 pounds of water per pound of dry air.
That's within the ASHRAE comfort zone, so a house with well-shaded
windows and minimal indoor electrical use would be comfortable on
an average day.
I would like to do something very simple?(not?fancy,?not?too?pricey)??
to try to make use of the fact that I have about 750 sq ft of basement
slab in the ground to provide cooling. ?
That's about 750ft^3x30Btu/h-F-ft^3 = 22.5K Btu/F of thermal mass,
counting some soil beneath at about R2 per foot, which could be useful
during a hot spell if it's kept cool with outdoor air on average days.
Otherwise, it will warm up quickly. The slab needs a vapor barrier
beneath to avoid adding humidity to house air.
One suggestion I have gotten is that some kind of collection of pipe
under the slab would allow me to make use od stac effect in summer -- *
drawing hot air out upstairs by keeping the house closed and drawing
air through the pipe to cool...
That's better done at night, when outdoor air is cooler. Warm air rises,
so in principle, a house with just one opening at the top might stay close
to the outdoor min. Two chimneys would work better, with air flowing down
one and up the other, vs conflicting flows in one chimney.
Anybody have any experience or very brass tacks practical advisce for
me on what I need to lay in the slab (soon) and how such a system
works, in terms of where the air intake and outlet need to be, etc.
???Also hoping not to create critter condos by doing this....Canb't
wait to hear yr ideas. ?Remember SIMPLE, please!
I'd forget the pipes and cool the basement slab and walls with outdoor air
at night, below the comfort zone, if it's unoccupied, with a fan (eg Lasko's
$50 2470 cfm 90 watt 2155A window fan) with a differential thermostat and
a humidistat that moves outdoor air through the basement when it is cooler
than basement air, as long as the basement air RH is under 60%, to avoid mold.
Ventilate the house at night down to a low comfort temp with another fan
with a differential thermostat and a humidistat and a low limit thermostat.
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